Merge r1705194, r1705823, r1705826, r1705828, r1705833, r1706275, r1707230, r1707231...

Merge r1705194, r1705823, r1705826, r1705828, r1705833, r1706275, r1707230, r1707231 from trunk:

mod_ssl: forward EOR (only) brigades to the core_output_filter().

mod_ssl: don't FLUSH output (blocking) on read.
This defeats deferred write (and pipelining), eg. check_pipeline() is not
expecting the pipe to be flushed under it.
So let OpenSSL >= 0.9.8m issue the flush when necessary (earlier versions
are known to not handle all the cases, so we keep flushing with those).

mod_ssl: follow up to r1705823.
Oups, every #if needs a #endif...

mod_ssl: pass through metadata buckets untouched in ssl_io_filter_output(),
the core output filter needs them.

Proposed by: jorton

mod_ssl: follow up to r1705194, r1705823, r1705826 and r1705828.
Add CHANGES entry, and restore ap_process_request_after_handler()'s comment
as prior to r1705194 (the change makes no sense now).

mod_ssl: follow up to r1705823.
We still need to flush in the middle of a SSL/TLS handshake.

mod_ssl: follow up to r1705823.
Flush SSL/TLS handshake data when writing (instead of before reading),
and only when necessary (openssl < 0.9.8m or proxy/client side).

mod_ssl: follow up to r1707230: fix (inverted) logic for SSL_in_connect_init().

Submitted by: ylavic
Reviewed/backported by: jim

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1715014 13f79535-47bb-0310-9956-ffa450edef68